Experimental study on damage of slope under drying and wetting cycle based on DC electric method.

In order to investigate the seepage law and crack development characteristics of dump slopes, as well as the impact on slope stability during drying and wetting cycles, a simulation test slope system was constructed in a rainfall environment, specifically designed to mimic the engineering conditions of dump slope. The apparent resistivity response formula for the seepage and crack development processes was derived based on the three-phase medium theory of rock-soil bodies and Maxwell's conductivity formula. The geoelectric field characteristics pertaining to slope damage and the corresponding patterns of alteration were comprehensively investigated. The results demonstrate a negative correlation between resistivity and slope water content, with resistivity increasing as cracks develop and decreasing with water infiltration. The progression of crack formation in a rainfall environment on a dump slope can be categorized into three stages: The initial phase involves the saturation of the slope as water content increases. Subsequently, the second phase entails the initiation and expansion of capillary zones, along with the formation of dominant waterways. Lastly, the third phase encompasses the formation and expansion of cracks within the dumping site. The occurrence of sudden changes and abnormal fluctuations in apparent resistivity within a saturated slope signifies the presence of cracks and weak surfaces, leading to gradual and irreversible damage. This phenomenon serves as an indicator of slope damage and can be utilized for the early prediction of slope instability.

The influence of distance weight on the inverse distance weighted method for ore-grade estimation.

In order to study the influence of distance weight on ore-grade estimation, the inverse distance weighted (IDW) is used to estimate the Ni grade and MgO grade of serpentinite ore based on a three-dimensional ore body model and related block models. Manhattan distance, Euclidean distance, Chebyshev distance, and multiple forms of the Minkowski distance are used to calculate distance weight of IDW. Results show that using the Minkowski distance for the distance weight calculation is feasible. The law of the estimated results along with the distance weight is given. The study expands the distance weight calculation method in the IDW method, and a new method for improving estimation accuracy is given. Researchers can choose different weight calculation methods according to their needs. In this study, the estimated effect is best when the power of the Minkowski distance is 3 for a 10 m × 10 m × 10 m block model. For a 20 m × 20 m × 20 m block model, the estimated effect is best when the power of the Minkowski distance is 9.

The effect of high mobility group box-1 protein on immune function of human T lymphocytes in vitro.

OBJECTIVE: To investigate the effect of high mobility group box-1 protein (HMGB1) on immune function of human T lymphocytes in vitro and explore its potential role in cell-mediated immune dysfunction. METHODS: Fresh blood was obtained from healthy adult volunteers and peripheral blood mononuclear cells (PBMCs) were isolated, then rhHMGB1 was added to PBMCs. Cell viability was assessed by thiazolyl blue (MTT) assay. Four-color flow cytometric (FCM) analysis was used for the measurement of CD3, CD8 expression. Reverse transcription-polymerase chain reaction amplification was performed to detect respective gene expression of interleukin-2 (IL-2), IL-2 receptor (IL-2R) alpha. RESULTS: (1)Proliferation of T lymphocytes was not affected by rhHMGB1 in low concentrations, while continued exposure of T cells to 500-1000 microg/L rhHMGB1 for 48 hours resulted in a decrease in MTT assay. (2) Different stimulating time and dosages of rhHMGB1 did not alter CD4 expression of CD3+ T lymphocytes. rhHMGB1 stimulation provoked a dose-dependent and time-dependent increase in Th2 subset and lowering in ratio of Th1 to Th2. (3) Compared with the untreated cells, when the cells were co-incubated with rhHMGB1 (10 microg/L) for 12 hours, mRNA expressions of IL-2 and IL-2R were significantly up-regulated. At 48 hours, in contrast, gene expression was relatively lower in T cells after exposure to 100-1000 microg/L rhHMGB1. CONCLUSION: These data demonstrated that HMGB1 had a dual influence on immune functions of T lymphocytes.

[Effects of Xuebijing injection on multiple organ dysfunction and mortality in rats with delayed resuscitation for scald injury].

OBJECTIVE: To investigate the effects of Xuebijing injection on multiple organ dysfunction and mortality in rats with delayed resuscitation after scald injury. METHODS: Wistar rats were subjected to a 30% total body surface area (TBSA) full-thickness scald injury in the experimental groups. One hundred and thirty male Wistar rats were randomly divided into sham scald group (n=10), thermal injury group (n=60, 40 ml/kg normal saline was infused peritoneally 6 hours postburn), and Xuebijing treatment group (n=60, 4 ml/kg Xuebijing injection was injected twice a day in addition to delayed resuscitation). Animals of the thermal injury group and Xuebijing treatment group were re-divided into three subgroups according to the different time points of treatment: 2 hours before scald (n=20), 2 hours after scald (n=20), and 12 hours after scald (n=20). Multiple organ function parameters and 7-day mortality were determined in all the groups. RESULTS: The mortality of animals with Xuebijing treatment at 12 hours postburn was significantly lower than that of scald controls (75.0% vs. 40.0%, P<0.05). In comparison with scald group, the animals in Xuebijing treatment group were found to have significantly decreased values of organ functional parameters at 12 hours postburn, including serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (Cr) and creatine kinase (CK, P<0.05 or P<0.01). CONCLUSION: These findings indicate that Xuebijing injection could obviously lower the mortality of rats with delayed resuscitation after burn injury, and it markedly protects against multiple organ dysfunction secondary to severe burns.

[Suggestive guideline for respiratory support in emergency--stepwise breath management].

OBJECTIVE: To propose a guideline of respiratory support for emergency patients. METHODS: To summarize the experiences gained in giving stepwise respiratory support (SRS) in 2,548 patients for emergency care (including 1,823 trauma patients and 725 non-trauma patients) between 1992 to 2002. RESULTS: There were 1,876 male and 672 female patients with the ratio of male to female 2.79:1. The age of patients ranged between 4 to 86 years, and the mean age of traumatic patients was (32.3+/-19.8) years, and the dominant ages were between 20 to 39. The mean age of non-traumatic patients was (65.2+/-17.3) years, and the dominant ages were between 50 to 69. The traumatic and non-traumatic patients accounted for 60.2% and 32.0% of all patients, respectively. The respiratory management included resuscitation positioning in 816 (32.0%), open airway and suctioning in 314 patients (12.3%), oxygenation through nostril or nasal intubation in 2,311 patients (90.7%), oxygenation by mask in 124 patients (4.9%), endotracheal intubation in 254 patients (10.0%), thyrocricocentesis or cricothyrotomy in 25 patients (1.0%), tracheotomy in 195 patients (7.7%), percutaneous tracheotomy in 58 patients (2.3%). SRW management included two types, four steps and ten ways. The two types included traumatic and non-traumatic; the four steps and ten ways included first step of manual treatment (including (1) resuscitation positioning, (2) open airway and suction and (3) chest-back press), second step oxygenation (including (4) oxygenation through nostril or nasal intubation, (5) oxygenation by mask, (6) endotracheal intubation), third step invasive airway support (including (7) thyrocricocentesis or cricothyrotomy and (8) tracheotomy or percutaneous tracheostomy), fourth step mechanic ventilation (covering (9) manual ventilation and (10) mechanical ventilator). CONCLUSION: The series of SRS management plan and principles can improve the respiratory support in rescuing emergency patients efficiently.

[Effect of intensive insulin therapy on serum proinflammatory cytokine levels in patients with severe trauma].

OBJECTIVE: To investigate the effect of intensive insulin therapy on serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and C reaction protein (CRP), all of which reflected the inflammatory status in patients with severe trauma. METHODS: Forty patients with severe trauma [injury severity score (ISS)>or=20] were randomly divided into intensive insulin therapy group and control group. Enzyme-linked immunoadsorbent assay (ELISA) method was used to determine the TNF-alpha and IL-6 levels within 72 hours after admission. RESULTS: Serum levels of TNF-alpha, IL-6 and CRP in patients received intensive insulin therapy were significantly lower than those in patients without the therapy (P<0.05 or P<0.01). CONCLUSION: Intensive insulin therapy can attenuate the systemic inflammatory response to trauma. The anti-inflammatory actions of insulin, as well as its glycemia controlling effects, might contribute to the improved outcomes of patients with severe trauma.